She persisted in this belief for the first 2 years of medical school at Harvard. When she received her gross anatomy exam back with the professor's comment that it was the exam of a general surgeon, she described herself as "totally offended."

She entered third year fascinated by dermatology and the idea that skin could manifest problems from any organ system.

Then she saw her first operation as a third-year medical student at Harvard's Cambridge Health Alliance.

"I saw a patient get rolled into the operating room with a problem, and then when the patient left the operating room he didn't have that problem anymore," McKinley said.

"I loved the high impact that surgeons had on patients and on their diseases. I also loved the relationship between surgeons and their patients -- that patients trust surgeons so much that they give them the opportunity to use a knife on their body and rearrange their organs or cut off their breast. I was compelled by the intensity of that relationship."

The Hopewell Junction, N.Y., native ditched her plans of becoming a dermatologist, did electives to rule out surgical specialties, and applied for general surgery residency. She is now a general surgery intern at Massachusetts General Hospital in Boston, Mass.

First Cuts in the Operating Room

McKinley already had enjoyed more independence in the operating room than the typical medical student by working in a community hospital with few surgical residents. When she filled in for an intern during an umbilical hernia repair, she did the entire case under the attending's guidance.

"I was so worried because I had done something without waiting for the attending to tell me what to do. But then he said, 'Oh look, I didn't even have to tell you that time. See, anyone can learn how to be a surgeon.' He was pleased."

Intern year has been about taking that step between watching someone make the incision and making the incision yourself, she said.

After one month on the job, McKinley has assisted with melanoma excisions, lumpectomies, thyroidectomies, parathyroidectomies, and anorectal cases. She is on a private general surgery service and is allowed to do any kind of case that a general surgeon or a surgical oncologist does.

"There have definitely been moments where I cut too hard, or I didn't cut hard enough, or I didn't burn the right structure with electric cautery. But I think overall I've surprised myself by how quickly I can pick up on something if I see it a few times."

The stress, she says, is considerable. "You're wielding a weapon on a person who is unconscious and you don't want to hurt that person, but you're also trying to prove to the attending that you're not a total klutz."

Front Line on the Floors

Outside of the operating room is a different kind of stress -- one that involves clinical decision-making. Interns get frequent pages from nurses and other teams about how patients are doing. Sometimes there is a senior resident around to run a plan by, but other times the intern has to make an initial call.

"You have to do something with that page. You're the front line," she said.

One of her most common pages is for low urine output.

Possibilities race through her mind: "Do they need more fluid? Or are they tiny and it should be low? Has their Foley been pulled overnight, and they haven't voided yet, and they're now in urinary retention? Do they need Lasix because they had acute kidney injury and their kidneys aren't working very well, and now they have a new oxygen requirement?"

Other pages in her first 4 weeks on the job have included:

Patient is tachycardic to 130 and dizzy

New onset atrial fibrillation

Patient has systolic blood pressure of 80

Patient has acute onset of abdominal pain and finger-stick blood glucose of 38

The pages don't stop when she is operating. A circulating nurse reads them aloud so McKinley can make decisions. "It's really stressful when you're physically tied to a place," she said. "Obviously your priority is the patient in front of you."

After seeing a patient on the floor, her first question is: "Can I handle it myself or not?"

The answer to that question takes a lot of self-knowledge. "What level of functioning are you at without supervision? How confident are you you can identify someone sick?" she said.

McKinley sometimes struggles with confidence in her clinical instincts. She described her uncertainty about when to transition a postoperative patient from "nothing by mouth" to liquids.

"If this patient gets Zofran she could be fine with sips, or she will aspirate and get pneumonia. I'm imagining an ICU admission based on sips of Crystal Light," she said.

"I think both scenarios are right. There are universes in which these could both happen, but we only get one shot at making this decision."